1. Field of the Invention
The present invention relates to a frame counter device for frame counting of photo film. More particularly, the present invention relates to a frame counter device for counting up or down at each time when one frame is exposed on photo film, in which a counted number can be clearly indicated.
2. Description Related to the Prior Art
A camera or a lens-fitted photo film unit incorporates a frame counter device, which counts and indicates the number of frames exposed on photo film or the number of frames remaining unexposed on the photo film. The frame counter device includes a counter disk and a counter window. The counter disk has a train of numbers arranged on its top face in an arc shape. The counter disk is rotated by one step at each time when the photo film is wound by one frame. The counter window renders one number in the train number observable externally. A pointer is printed on the outside of the camera or a cardboard wrapper around the lens-fitted photo film unit, and has a triangular shape or the like to point the center of the window.
The lens-fitted photo film unit includes a housing, which incorporates a simple mechanism for taking exposures. The housing is loaded with an unused photo film cassette in a state where unexposed photo film is entirely drawn from it and provisionally wound in a roll form. When a winder wheel of the lens-fitted photo film unit is rotated after exposing each frame, the photo film is wound into the photo film cassette by a length of one frame. After exposing all available frames, the lens-fitted photo film unit is simply forwarded to a photo laboratory without rewinding operation. The photo film in the lens-fitted photo film unit is subjected to photofinishing, before photo prints are supplied to the user and the photo film being developed is returned to him or her.
There is an IX-240 type of the photo film cassette recently widespread and used in a system referred to as "Advanced Photo System" (trade name). The IX-240 type of the photo film cassette is characterized in its small size. The volume of the IX-240 type of the photo film cassette is 75% as small as that of the conventional 135 type of the photo film cassette. The size of the camera and the lens-fitted photo film unit for use with the IX-240 type of the photo film cassette is reduced. Accordingly, the counter disk has a small size. It is likely that the numbers arranged in the train on the counter disk are very small and difficult for users to recognize exactly and quickly.
In the photo film cassette of the IX-240 type, there is no perforation between a first frame and a leader of the photo film. In the frame counter device of the remainder indicating type, it is likely that there occurs failure in stepwise rotation of the counter disk upon photo film movement after exposing a final frame in the lens-fitted photo film unit. Rotation of the counter disk from the number "1" to the triangular indicia is insufficient. Thus, the completion of the use of the photo film is unclearly indicated to users.